Blender Git Loki

Cleanup: Declare variables where initialized

Cycles: Increase instance limit for OptiX acceleration structure building

For a while now OptiX had support for 28-bits of instance IDs, instead of the initial 24-bits (see also
value reported by OPTIX_DEVICE_PROPERTY_LIMIT_MAX_INSTANCE_ID). This change makes use of
that and also adds an error reported when the number of instances an OptiX acceleration structure is
created with goes beyond the limit, to make this clear instead of just rendering an image with artifacts.

Manifest Tasks: T81431

Bone Overlay: support bone wireframe opacity settings.

When weight painting the bone overlay is extremely intrusive,
effectively requiring either extensive use of hiding individual
bones, or disabling the whole bone overlay between selections.

This addresses the issue by adding two bone opacity sliders that
are used for the 'wireframe' armature drawing mode. One directly
controls the opacity in a uniform way. The other one allows fade
based on the depth between the near and far clip planes in order
to provide an automatic visual cue about which bones are closest.

Armature: fix bad B-Bone deformation blending with Preserve Volume.

The double quaternion blending method in addition to the deformation
matrix of each bone requires their rest matrices. For ordinary bones
this literally should use the bone rest matrix without any ambiguity.

However, it was also using the bone rest matrix for all of its
B-Bone segments, which is incorrect and causes strange deformation
in some cases involving extreme non-uniform scale, especially
at boundaries between different B-Bones.

This changes both the Armature modifier and the Armature constraint
to use the actual segment rest matrices. Unlike bones, these can have
scale even in rest pose, so normalization is required.

Weight Paint: avoid creating very small values with locked weights.

When painting using Auto-Normalize or Lock Relative with some
groups locked, the locked weights may not add up precisely to
1 because of precision limitations, which results in creating
nonzero weights close to FLT_EPSILON. With Lock Relative display
mode this is very obvious and annoying (random red points amid
black or blue), so add an epsilon check to consider less than
1e-6 unlocked weight to be the same as 0.

In addition, in cases when no weight can be painted due to locks,
don't create vertex group entries at all if they don't exist yet.

Armature: add B-Bone lengthwise scaling and custom handle scaling options.

In addition to the base bone transformation itself, B-Bones have
controls that affect transformation of its segments. For rotation
the features are quite complete, allowing to both reorient the
Bezier handles via properties, and to control them using custom
handle bones. However for scaling there are two deficiencies.

First, there are only X and Y scale factors (actually X and Z,
but this is the legacy naming), while lengthwise all segments
have the same scaling. The ease option merely affects the shape
of the curve, and does not cause actual scaling.

Second, scaling can only be controlled via properties, thus
requiring up to 6 drivers per joint between B-Bones to transfer
scaling factors from the handle bone. This is very inefficient.

This patch addresses these deficiencies by adding Length scale
inputs, and providing toggles to apply custom handle local scale
channels to the now four scale-related properties. The 'Length'
name is used to avoid confusion due to the X/Y vs X/Z naming.

The two Length scale inputs control the ratio between the lengths
of the start and end segments of the bone: although for convenience
two inputs are provided, the whole chain is still uniformly scaled
to fit the curve.

A Scale Easing option is provided to multiply the easing value
by the Length scale factors to synchronize them - this produces
a natural scaling effect where both the shape of the curve and
the scale is affected.

The second issue is addressed by providing toggles for each handle
that multiply each of the X, Z, Length and Ease values by the matching
Local Scale channel of the handle bone, thus replacing trivial drivers.
The Scale Easing option has no effect on this process since it's easy
to just enable both Length and Ease buttons.

Finally, this fixes a strange behavior where the segments were not
actually scaled in the Y direction to match their actual length, thus
producing gaps or overlap depending on the shape of the curve. For
transformation the change should be very small if enough segments
are used, but this will affect the results of the Copy Transforms
and Armature constraints, so a backwards compatibility option is
provided. Newly created bones default to the new behavior.

Differential Revision: https://developer.blender.org/D9870

Copy Transforms: implement Invert, Fix Shear and more Mix options.

This constraint can be naturally viewed as a prototype for a future
4x4 matrix math node (or subset thereof), since its basic semantics
already is matrix assignment. Thus it makes sense to add math options
to this constraint to increase flexibility in the meantime.

This patch adds support for several operations that would be useful:

- An option to fix shear in the incoming target matrix.
- An option to invert the target matrix.
- More ways to combine target and owner matrix.

Shear is known to cause issues for various mathematical operations,
so an option to remove it at key points is useful. In the future node
system this would be a separate operation, but due to the limits of
the constraint stack it has to be built in for now.

Inverting a matrix is also an operation that can be useful to have.
For some uses it may be useful to invert components separately, so
implement this by checking the Mix mode setting to avoid UI options.

Finally, add two more ways to combine the matrices (multiplied by
two due to the necessity for the Before/After choice). Now there
are three combine modes:

Full implements regular matrix multiplication as the most basic option.

Split Channels combines location, rotation and scale separately.
Looking at D7547 there is demand for such a mode in some cases,
and even with nodes it's cumbersome to rig manually every time.

Finally, Aligned emulates the 'anti-shear' Aligned Inherit Scale mode,
and basically uses Full for location, and Split for rotation/scale.

Differential Revision: https://developer.blender.org/D9469

Limit Rotation: add an Euler Order option and orthogonalize the matrix.

Since Limit Rotation is based on Euler decomposition, it should allow
specifying the order to use for the same reasons as Copy Rotation does,
namely, if the bone uses Quaternion rotation for its animation channels,
there is no way to choose the order for the constraint.

In addition, add a call to orthogonalize the matrix before processing
for the same reasons as D8915, and an early exit in case no limits are
enabled for a bit of extra efficiency.

Since the constraint goes through Euler decomposition, it would remove
shear even before the change, but the rotation won't make much sense.

Differential Revision: https://developer.blender.org/D9626

Constraints: add support for a new Owner Local Space for targets.

Add a new transformation space choice for bone constraints, which
represent the local transformation of the bone in the constraint
owner's local space.

The use case for this is transferring the local (i.e. excluding the
effect of parents) transformation of one bone to another one, while
ignoring the difference between their rest pose orientations.

Owner Local Space replaces the following setup:

* A `child` bone of the `target`, rotated the same as `owner` in rest pose.
* A `sibling` bone of the `target`, positioned same as `child` in rest
pose and using Copy Transforms in World Space from `child`.
* The `owner` bone constraint uses Local Space of `sibling`.

(This analogy applies provided both bones use Local Location)

Since the space list is getting long, this adds a couple of separators.

Differential Revision: https://developer.blender.org/D9493

Constraints: refactor the D7437 patch adding Custom Space for constraints.

As mentioned in the comments to that patch, I had an idea for
a different way to do some technical aspects, but it was too
complicated to force changes in the original patch. Thus I submit
this follow up patch.

First, instead of modifying all the get_constraint_targets and
flush_constraint_targets callbacks, introduce wrapper functions
for accessing constraint targets, convert all code to use them,
and handle the new reference there uniformly for all constraints.

This incidentally revealed a place in the Collada exporter that
didn't clean up after retrieving the targets.

Also, tag the special target with a flag so other code can
handle it appropriately where necessary. This for instance
allows dependency graph to know that the Use B-Bone Shape
option doesn't affect this specific target.

Finally, rename and simplify the function for initializing the
custom space, and make sure it is called everywhere necessary.

Differential Revision: https://developer.blender.org/D9732

Surface Deform: optimize memory allocation in the evaluation code.

Using malloc to allocate a temporary array for each vertex,
which most commonly contains just 4 elements, is not efficient.
Checking the mode with a switch is also better.

Finally, a one line UI fix: the strength option is not bind specific.

Differential Revision: https://developer.blender.org/D10040

Cloth: completely exclude fully pinned triangles from collision.

Currently such triangles are effectively already excluded, because
the calculated forces are not applied to pinned vertices. However
these forces are still being computed, which is inefficient.

This adds an early check for triangles where all vertices are
pinned during BVH overlap detection, which significantly speeds
up certain use cases with big fully pinned areas that happen to
overlap a collider. In case of self collision both triangles must
be fully pinned to exclude safely, because the computation is
symmetric and handles two triangles at the same time.

Differential Revision: https://developer.blender.org/D10041

Surface Deform: optimize handling of the vertex group weight.

There is no need to first copy weights to a separate array,
or create the data layer if it doesn't exist. The threaded
code can retrieve the weight directly from the layer.

Differential Revision: https://developer.blender.org/D10015

UI: Use Eyedropper Cursor with Sample Weight Tool

While using the Sample Weight tool in Weight Paint mode, user eyedropper mouse cursor.

Differential Revision: https://developer.blender.org/D9431

Reviewed by Pablo Vazquez

UI: Show Weight Value with Sample Weight Tool

While using the Sample Weight tool in Weight Paint mode, show weight value in tool header.

Differential Revision: https://developer.blender.org/D9432

Reviewed by Pablo Vazquez

Fix T84326: No ID for geometry nodes instances after scattering

Instances are created with an "index" parameter used for persistence over
time through animation. Currently the geometry nodes instancer passes
the index in the array for this value, but the arrays created by the
"Point Distribution" node aren't necessarily stable in this way when
the input mesh is deformed. In D9832 we already mostly solved this
problem with an `id` attribute. The solution here is to create instances
with this attribute as well.

It's important to note that deforming the instanced points *after*
distribution will usually be a better solution for this problem. This
solution is likely still important though.

Differential Revision: https://developer.blender.org/D10024

UndoSystem: Early out from core undo/redo handlers when undo step is NULL.

Also added `undosys_stack_validate` debug check to redo case.

Cleanup: Undo system: minor simplification in non-debug code.

Fix T84469: Online manual raises an exception with key-map options

Report an error instead of raising a Python exception.

Currently these properties aren't written to the manual
so it's best to show an error.

Fix T84142: crash when mirroring hair emitted from vertices

The hair mirroring code seems to expect that hair is emitted from faces.
The PE_mirror_x contains the following expression: mirrorfaces[pa->num * 2].
This only makes sense when pa->num is a face index.

The simplest short term solution is to disable the mirror operator when
the particles haven't been emitted from faces.

Diffferential Revision: https://developer.blender.org/D10002